Fasting

Bukhari :: Book 3 :: Volume 31 :: Hadith 153

Narrated Abu Bakr bin 'Abdur-Rahman:

My father and I went to 'Aisha and she said, "I testify that
Allah's Apostle at times used to get up in the morning in a state
of Janaba from sexual intercourse, not from a wet dream and then he
would fast that day." Then he went to Um Salama and she also
narrated a similar thing.